This invention relates generally to analog-to-digital converters, and particularly to techniques for digitizing a recurring analog signal containing high frequency components.
Various circuit arrangements presently used in sampling oscilloscopes can determine the amplitude of many points on a high frequency analog signal. One disadvantage of these methods is that only one sample is obtained for each repeat of the signal. If a large number of samples is required, the total time involved may be unacceptably long.
Various circuit arrangements, known as analog-to-digital flash converters, have been used to digitize high frequency waveforms in a single occurrence of the signal. One disadvantage of these methods is that a large number of comparators, divider components, and logic circuits are required. If the amplitude of each sample of the analog signal is to be determined to one part in 32, for example, than 32 high speed comparators are needed. The circuit becomes complex and expensive.
Various circuit arrangements known as successive approximation analog-to-digital converters have been used to digitize moderate frequency waveforms. One disadvantage of these methods is that the digitization rate is comparatively slow.
A principal object of this invention is to provide high sampling rate digitization of a repetitive analog signal with reduced complexity and expense and without the above mentioned disadvantages of existing methods.